BEVEL PROTRACTORS / Universal bevel protractor: Bevelprotractorsarenothingbutangularmeasuringinstruments. Typesofbevelprotractors. Experiment 5. AIM: Study and angular measurement of a given piece using bevel protractor. Study of dial indicator & its constructional details. A bevel protractor is a graduated circular protractor with one The bevel protractor is used to establish and test angles to very.
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A protractor is a measuring instrumenttypically made of transparent plastic or glass, for measuring angles. Radian-scale protractors measure angles in radians.
Most protractors are divided into equal parts. Some precision protractors further divide degrees into arcminutes.
They are used for a variety of mechanical and engineering-related applications. One common use is in geometry lessons in schools. Some protractors are simple half-discs. More advanced protractors, such as the bevel protractorhave one or two swinging arms, which can be used to help protractof the angle.
A bevel protractor is a graduated circular protractor with one pivoted arm; used for measuring or eperiment off angles. Sometimes Vernier scales are attached to give more precise readings. It has wide application in architectural and mechanical drawing, although its use is decreasing with the availability of modern drawing software or CAD.
Universal bevel protractors are also used by toolmakers; as they measure angles by mechanical contact they are classed as mechanical protractors. The bevel protractor is used to establish and bevdl angles to very close tolerances.
Protractor – Wikipedia
The bevel protractor consists of a beam, a graduated dial and a blade which is connected to a swivel plate with Vernier scale by thumb nut and clamp. When the edges of the beam and blade dxperiment parallel, a small mark on the swivel plate coincides with the zero line on the graduated dial.
Since the spaces, both on the main scale and the Vernier scale, are numbered both to the right and to the left from zero, any angle can be measured. The readings can be taken either to the right or to the left, according to the direction in which the zero on the main scale is moved. Twenty four spaces on the Vernier scale equal in extreme length twenty three double degrees [ clarification needed ]. Read off directly from the main scale the number of whole degrees between 0 on this scale and the 0 of the Vernier scale.
Then count, in the same direction, the number of spaces from the zero on the Vernier scale to a line that coincides with a line on the main scale; multiply this number by 5 and the product will be the number of minutes to be added to the whole number of degrees. Zero on the vernier scale has moved 28 whole protracttor to the right of the 0 on the main scale and the 3rd line on the vernier scale coincides with a line upon the main scale as indicated.
Multiplying 3 by 5, the product, 15, is the number of minutes to be added to the whole number of degrees, thus indicating a setting of 28 degrees and 15 minutes. Protractors have traditionally been one-sided. This is thought to be because early manufacturing methods set the experimentt of future production.
Unfortunately, the two number scales on a one-sided protractor often confuse learners when first xeperiment to measure and draw angles. However, inJake Adamson, a maths teacher working at Musselburgh Grammar School invented and patented the first two sided protractor trademarked “The Angler”.
This was a double sided protractor with one scale on each side, avoiding the confusion of having two scales together and enabling easier measuring and drawing of angles. From Wikipedia, the free encyclopedia.
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